I am seeing a similar issue with a second monitor plugged in. I am using nouveau and it crashes the X server and logs me out. I have attached a log of what happened. This is NOT connected with a screen lock, it happens randomly.
Display is: *-display description: VGA compatible controller product: GK107GLM [Quadro K1100M] vendor: NVIDIA Corporation physical id: 0 bus info: pci@0000:01:00.0 version: a1 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress vga_controller bus_master cap_list rom configuration: driver=nouveau latency=0 resources: irq:37 memory:d1000000-d1ffffff memory:70000000-7fffffff memory:80000000-81ffffff ioport:5000(size=128) memory:c0000-dffff ** Attachment added: "The text file shows the nouveau error and the X server crashing." https://bugs.launchpad.net/ubuntu/+source/linux-signed-hwe-5.8/+bug/1933609/+attachment/5536495/+files/CrashLog.txt -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1933609 Title: Locking screen crashes X/Wayland with nouveau when multiple monitors are plugged in To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-signed-hwe-5.8/+bug/1933609/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs